Access was denied to the service manager on the target computer.
This security error is usually caused by the user account not being an administrator of the target machine.
The Windows User token has become corrupted and a restart of the background service (PDQInventory or PDQDeploy) on the console computer is needed.
In some instances this error only appears when deploying or scanning Windows 7 and Windows 2008 R2 targets that have their Windows Firewall turned off.
Ensure that the user is a member of the computer's Administrator group or is otherwise an administrator of the computer.
Restart the Background Service. (Go to File > Preferences and select the Background Service panel). Stop and the start the service. Retry the scan or deployment. In many cases restarting the service corrects the problem.
You may need to change the Authentication used when deploying to this computer.
If the target is a Windows 7 or Windows 2008 R2 and the Windows Firewall is turned off (and needs to stay off) then the user credentials that run the Background Service must have Administrative rights on the target machines. You can configure the Background Service credentials via File > Preferences.
Modify Service Manager TCP Connection
If the problem persists after restarting the background service you may need to modify the Service Manager TCP Connection settings in Preferences > Performance. (Note: This setting is not available in XP or 2003). Try setting the value to Timeout 5 seconds. If the problem still persists try the Disabled value.
**Added based on comments below**
Verify PDQ Inventory or PDQ Deploy service is not running as LocalSystem
Occasionally the Background Service (Preferences > Background Service) credentials aren't honored in the actual Windows' services for PDQ Inventory and PDQ Deploy. In these cases open up Services.msc and verify that the Log On As value is NOT set to Local System. If it is, you may need to change the logon value inside of Services to match the credentials specified in the Background Services panel.